When Thunderbird 2 is selecting the pod, it is clear that Pod 4 is being selected. When we see Thunderbird 2 moving out of the hanger Pod 2 is next to it indicating Pod 3 had been chosen. This goof is also seen in the episodes "Sun Probe", "Vault of Death", "Move - And You're Dead", "Martian Invasion" and "The Perils of Penelope". This is because footage of the TB2 launch from the first episode ("Trapped In The Sky") has been used in the abovementioned episodes.