Just a little confused...help?

Okay I watched this movie and I actually really liked it I was just confused by one thing. If you can explain it to me let me know. In the one scene where James Marsters' character is explaining everything he said to take off your clothes because you're less of a target then but the two people that had already died, the security guard and nurse, were both wearing the tank top and shorts too. Anyone understand this? Please help.

"Love isn't brains, children, it's blood -- blood screaming inside you to work its will."~~~~Spike