Movement by the astronauts was detected by the spacecraft's inertial measurement unit and the astronauts' biomedical sensors, and also indicated by increases in oxygen spacesuit flow, and sounds from Grissom's stuck-open microphone. There was no evidence to identify the movement, or whether it was related to the fire. The stuck microphone was part of a problem with the communications loop connecting the crew, the Operations and Checkout Building, and the Complex 34 blockhouse control room. The poor communications led Grissom to remark: "How are we going to get to the Moon if we can't talk between two or three buildings?" The simulated countdown was put on hold again at 5:40 pm while attempts were made to troubleshoot the communications problem. All countdown functions up to the simulated internal power transfer had been successfully completed by 6:20 pm, but at 6:30 the count remained on hold at T minus 10 minutes.