Will using "bridge mode" with both NICs plugged into the same switch cause a loop?

We're got a very backwards network here. No VLANs, random IPs everywhere, etc. This is my issue:

Our software department needs access to the Internet in their lab, but we need to log all their traffic. My thought is, I could put an Untangle box online in Bridge Mode, let Untangle log all the traffic & let our normal proxy do the filtering.

If I run Untangle in Bridge Mode and plug both NICs into the switch, will this cause a network loop? The lab network is intermixed with all the other IPs on the network.

Thanks!