I'm relatively sure you would run into issues unless you have multiple TD Ameritrade accounts and I'm not sure if it would work even if you could change the install directory due to Windows Registry entries... I run Thinkorswim on two PC's and a laptop using the same account but my PC's disconnect if I take my laptop with me to customer sites due to licensing... You can't have Thinkorswim open in the same account on different networks...
What, exactly, are you wanting to accomplish...??? Worst case scenario, TD Ameritrades Thinkorswim technical support could answer your question...
Edited to add: I just started a second install and it asked if I wanted to update my existing install or install another instance in a different directory... I installed the second instance and will do some additional testing... It would be slick to be able to have a live and a paper trading account open concurrently...