They did not take them in coaches to deport them. They took them to house them in the community, unvetted.
They were taken elsewhere to be processed. If your argument is that they shouldn't have been allowed to leave the facility and should have been sent to a third country, it is possible to do that without killing anyone.
What you do is, you get a navy ship to approach the 'small boat' you point a gun at them (very common at have armed police at places such as ports or airports) and you tell them to turn the boat around and go back to France.
Are you not familiar with the English Channel? It's dangerous enough making the crossing one way. Expecting them to go back (presumably ignoring tides and weather conditions) is not something you can do if you want to prevent drowning. But then you are apparently happy to gun them down in the channel. Let's hope it's not Cowes week.
You protect your country from unkown invaders.
Most illegal immigrants are people who enter the country legally and overstay their visa. Are we killing them too? I think we can deal with a few people crossing on boats without abandoning our humanity and condemning them to drowning.
It's pathetic that we have gotten to the point that any show of backbone is vilified and met with gasps of horror. Guns?! Actual enforcement of our borders?! How barabaric!!
Using guns against people in dinghies would be pathetic.