Birling's appalled - not by suicide, but by theft and shame
1. Arthur Birling starts to take the situation seriously for the first time. His son's stolen money from the company to help support Eva/Daisy, and Birling decides that he needs to "cover this up" as soon as he can
2. In the middle of Eric's story, Arthur orders the women to leave
3. Eric's involvement has gone too far for the Birling family. He'd have had an illegitimate child with a prostitute. This would have brought shame on the family