There is no established way to parse a multi-line cell from text. If you really intend to use this, you should use a less-ambiguous table format. You'll need to have row dividers. A typical divided format looks thus. Here, it's possible to find the "1\nb" entry.

+---+---+---+
| A | B | C |
+---+---+---+
| 1 | 2 | 3 | 
| b |   |   |
+---+---+---+
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Further, Text::Table w/ newlines has been out of date since about a week after it was written. Text::Table has been able to write out newline-containing fields since then.