It is always a good idea to save before running a script that has this potential. You might be able to get out of the loop with a command/ctrl + . (period/fullstop). Most infinite loops occur in REPEAT...UNTIL and WHILE...ENDWHILE conditions since it is easy for the terminal condition to never be met. I don't know if this is your situation, but a simple remedy is to put a simple counter inside the loop that will bail out after some large number of iterations. For example:
REPEAT
! Some useful code here
count = count + 1
IF count > 10^6 THEN 100
UNTIL pigs = "fly"
100: !Get out of loop free card
This example will count to one million before bailing out which may be excessive for your needs, but it should take well under 1000 seconds to execute (I recall testing the loops at around a millisecond once, but that was on a MUCH slower computer than anything we use now).
I have used a similar approach for loops where I couldn't predict the conditional value and it was easier to get out with the IF statement.
