Here is a rob skript but you could check if player is in the area way easier with worldguard.

Code (Text):

1. options:
2.     countdown: 1 #minutes
3.     robtime: 10 #seconds
4.    
5.    
6. function checkarea(p: player) :: boolean:
7.     if x coord of {robarea::pos1} > x coord of {robarea::pos2}:      
8.         if {_p}'s x coord is more than {robarea::pos1}'s x coord:
9.             broadcast "fail3"
10.             return false
11.     else:
12.         if {_p}'s x coord is less than {robarea::pos1}'s x coord:
13.             broadcast "fail3"
14.             return false
15.  
16.     if x coord of {robarea::pos2} > x coord of {robarea::pos1}:      
17.         if {_p}'s x coord is more than {robarea::pos2}'s x coord:
18.             broadcast "fail3"
19.             return false
20.     else:
21.         if {_p}'s x coord is less than {robarea::pos2}'s x coord:
22.             broadcast "fail3"
23.             return false
24.        
25.     if z coord of {robarea::pos1} > z coord of {robarea::pos2}:      
26.         if {_p}'s z coord is more than {robarea::pos1}'s z coord:
27.             broadcast "fail3"
28.             return false
29.     else:
30.         if {_p}'s z coord is less than {robarea::pos1}'s z coord:
31.             broadcast "fail3"
32.             return false
33.  
34.     if z coord of {robarea::pos2} > z coord of {robarea::pos1}:      
35.         if {_p}'s z coord is more than {robarea::pos2}'s z coord:
36.             broadcast "fail3"
37.             return false
38.     else:
39.         if {_p}'s z coord is less than {robarea::pos2}'s z coord:
40.             broadcast "fail3"
41.             return false
42.     return true
43.        
44. command /rob <text>:
45.     usage: &7/rob <start/reset/pos1/pos2>
46.     permission: rob
47.     permission message: &cNo permission
48.     trigger:
49.         if arg-1 is set:
50.             if arg-1 is "start":
51.                 if {robbery::countdown} is not set:
52.                     if checkarea(player) is true:
53.                         if {robbery::timer} is not set:
54.                             send "Robbery started"
55.                             set {robbery::timer} to 0
56.                             set {robbery::player} to player
57.                             stop
58.                         else:
59.                             send "robbery inprogress"
60.                     else:
61.                         send "area"
62.                 else:
63.                     send "cooldown"
64.             else if player has permission "rob.admin":
65.                 if arg-1 is "reset":
66.                     delete {robbery::countdown}
67.                     send "reset"
68.                 else if arg-1 is "pos1":
69.                     set {robarea::pos1} to player's target block
70.                     send "pos1 set to %player's target block's location%"
71.                 else if arg-1 is "pos2":
72.                     set {robarea::pos2} to player's target block
73.                     send "pos2 set to %player's target block's location%"              
74.             else if player does not have permission "rob.admin":
75.                 send "&cNo permission"
76.         else:
77.             send "&7/rob <start/reset/pos1/pos2>"
78.                
79.  
80. every 1 second:
81.     if {robbery::timer} is set:
82.         if checkarea({robbery::player}) is true:
83.             add 1 to {robbery::timer}
84.             if {robbery::timer} >= {@robtime}:
85.                 send "Robbery succesfull" to {robbery::player}
86.                 set {robbery::countdown} to 60 * {@countdown}
87.                 delete {robbery::timer}
88.             else:
89.                 send action bar "%{@robtime} - {robbery::timer}%" to {robbery::player}
90.         else:
91.             delete {robbery::timer}
92.             send "robbery failed" to {robbery::player}
93.     if {robbery::countdown} is set:      
94.         subtract 1 from {robbery::countdown}
95.         if {robbery::countdown} <= 0:
96.             delete {robbery::countdown}
97.