I bought this game cheap on Steam the other day, and have just been trying the SP game. I am probably missing something obvious, but how do I get my squad members to open doors and engage the enemy? I tag the enemys using the snake cam, I position the squad by the door I want them to enter by, then I go in via another door, but my team do nothing - what key do I need to press to get them to do something? I am playing on the PC version.